Set-top boxes, digital video recorders, and other digital television products typically have a built-in 27 megahertz (MHz) system clock. Currently, communication devices embedded within such digital television systems use external crystals or clock inputs that are specific to the internal clock requirements of the communication device. These techniques do not implement an internal clock generator to specifically use a 27 MHz clock input. For example, the 2nd generation ISOmodem device embodiment depicted in FIG. 1 requires a fixed 4.9152 MHz clock input. As shown in FIG. 1, modem device 10 includes a clock interface 15 and phase-locked loop (PLL) and clock generation circuitry (collectively “PLL/clock generator”) 20.